Plants make several hormones that are important for growth and development. Some statements on plant hormones are given below:

A. Auxin is produced primarily in the root apices

B. Cytokinins are a smaller group of related compounds.

C. Gibberellins are a large group of related compounds defined not by their biological functions but by their structures.

D . Brassinosteroids are an important class of plant hormones, which control a broad spectrum of developmental reposes including pollen tube growth.

Which of the above combination of statement is correct